Thiophene derivatives of the benzanthrone series and process of preparing the same



Patented a. 14, 1930 NI E STATES PATENT OFFICE -7ABTI-IUR LUE'rrRINGHAus, or MANNHEIM, AND PAUL NAWIASKY Ann ALFRED EHR- I HARDT, or LUDWIGSI-IAFEN-ON-THE-RHINE, GERMANY, ASSIGNORS TO GENE AL ANILINR WORKS, rim, or NEW YORK, N. Y., A CORPORATION or DELAWARE THIO PHEN E DERIVATIVES OFTHE BENZANTHRON E SERIES AND PROCESS OF I PREPARING THE SAME I No Drawing. Application fi led November 30, 1928, Serial No. 322,962, and in Germany DecemberZ, 1927.

The present invention relates to the production of new condensation products ofBzlbenzanthronyl-thioglycollic acid or derivatives andlsubstitution products thereof which siare'soluble in alk'alis, and vat dyestuffs obtainable therefrom;

l/Ve have found that valuable condensation l i products of the ben zanthrone series are pro- I duced when Bzl-benzanthronyl thioglycollic :-,.;1o acid, or substitution products thereof with unoccupied 2-position, are treated with alkaline .condensing agents. New products, soluble in alkali, areso produced together with inconsiderable or larger amounts, according to the c methodof working employed, of compounds insoluble in alkali-or leuco-compounds ofvat dyestuffs, which can be readily separated by filtration'either directly, or aftercareful oxidation of ,the leuco compounds after the reactionmass has been diluted with water.

' Theialkalisoluble products'are readily precipitated from an aqueous solution thereof even by weak acids.

By a treatment with mild oxidizing agents,

; ithe aforesaid new condensation products undergo'further condensation into blue green substances posses-sing the character of-vat dyestuffs. This condensation can be effected, for

example, by the introduction of air into the 3 warmed alkaline solution, or by the addition of other oxidizing agents, such as ammonium persulfate, tothe alkaline solution. The oxidation may, however, also be effected by heating the dried intermediate products with nitrobenzene or with inert solvents, as for example trichlorbenzene, o-dichlorbenzene,

naphthaleneand the-like, in the presence of air, or'by warming their-solution in highly a 40 concentrated sulfuric acid for a short time,

' whereby, however, sulfonation easily takes ,place. .The progressof the reaction for the formation of these alkali soluble condensation products and their resulting condensation products which-give blue green dyeings from the vat, may probably be represented some what as follows:

' CO-l-alkaline CO OO-i-O -o Moreover, the esters, amides, nitriles and similar derivatives derived from the Bzl-benzanthronyl-thioglycollic acids, which by saponification are converted into Bzl-benzanthronyl-thioglycollic acid, with unoccupied 2-positions, and their substitution products and derivatives can be subjected to the action of alkaline condensing agents, preferably in the absence of water. The result bei ing that primary condensation products are obtained which are analogous to those above described, the main difference as regards their propertiesbeingthat they are, generally speaking, substantially more stable towards mild oxidizing agents, under the action of which they are only gradually and incompletely converted into the said blue green condensation products with the properties of vat dyestuffs. Withaqueous alcoholic alkalis the said condensation products form, for the most part, intensively colored solutions with strong fluorescence. After exposure to the action of saponifying agents, they behave in precisely the same manner as the condensation products of the free acids herein described,

- inasmuch as, like those, they are converted by weak oxidizing agents, into other condensation products possessing the character of vat dyestuifs.

The following examples will further illustrate the nature of the said invention which, however, is not limlted thereto. The parts are by weight.

- E wample 1 150 parts ofsolid potassiuinhydroxid are warmedto 170 C. with 50 parts of water, whereupon 30 parts of Bzl-benzanthronyl- I thioglycollicacid, with the melting point 220 diate "product may also be dissolved in 90 filtered off, dried and purified, as

boiling inert organlc sol,

' maintained C. are introduced into the'melt' at the same 7 temperature. The temperature 1s then ralsed,

while stirring, to 195 0., and the mixture is' maintained for half an hour at from 195 to i200? CmThe meltis then allowed to cool, is diluted with 3000 parts of water at 40 (1, filtered off from the insolubles and treated 5 with dilute hydrochloric acid; until no'fu'rther precipitation occurs. The brownish orange precipitate. is drled, andis boiled with 20 parts of nitrobenzene for a quarter of an'hour, in

order toconvert it into the blue green condensation product. The solutionacquires a green color, and the condensation product gradually separates out, for the most partlin the form of lustrous dark blue needles It is cooled down to 110? "0., filtered, thoroughly washed with warm nitrobenzene and benzene,

and. dried. j The conversion of the-intermediate product into the colored final product may also be effected by warming the filtered alkaline solution to 70 C. and passing air therethrough at that temperature, until no further increase in precipitation occurs; Thejcrude dyestuff is for example by extraeti'on'with' vents, such as nitrobenzene. The intermepercent sulfuric acid, and the solution be 1; from 95 to 100 o. for

' minute's. Thefinal product separates out on dilution with also in this case be effected by boiling wlth inwater. The purification can ert solvents. I

On precipitation from a solutionin concentrated sulfuricacid, in which it dissolves sparingly with a brownish violet color, the

colored condensation product forms blue ,green paste,

ton from a blue vat. Onexposure to the alrthe color changes into anextremely fast blue 7 green. I

If Bzl-b'enzanthronyl-thioglycollic acid be" ...replaced, by 6-chlor Bzl-benzanthronyl-thio- ,glycollic acid, a similar product, giving blue which gives blue dyeings on cotgreen dye ngs, is obtained.

Q Potassiumfhydroxid may be replaced by an equimolecular mixture of potassium by sub droxid and sodium hydroxid in the presence or absence of water.

E wample Z 10 parts of Bzl-benzanthronyl-thioglycollic acid are introduced into a mixture of 4100 parts of anhydrous pyridine and parts of melt then being kept for some hours at 90 C. The color of the pyridine solution therebyturns slowly from brown-to a darkblue. When no further change of the color-occurs, the cooled mixture is introduced into diluted acid, whereby a brownproductis precipitated, which then is transformed after filtering "by suctionand drying as describedin Example 1 into .the blue green condensation product therereferred to. i

Emma

5 vpartsof the ethylester ofBzl-benzanthronyl-thioglycollic acid, of a melting point from 135 to 138 0., preparedgby heating "B21-benzanthronyl-thioglyc'ollic "acid with ethyl'alcoh'ol and a'little concentrated sulfuric acid,} and parts of solid potassium hydrox d are introduced into l00parts of pyridineQand stirred until thecolor of the repotassium hydroxid,heated to (3., the I action mixture ceases to change. The brownaqueous caustic soda solution, the solution having an intensive'red color with orange "yellow fluorescence. In66 Bqsulfuric acid: a blue solution with: greeni'shtinge andred fluorescence-is obtained. Y

' For conversion into the condensation prod not of vat dye'stuff character, described in Example 1, a suitablemethod is to heat 2 parts of the crude product with 15 parts of "30? Be. caustic soda solution and 25" parts of watergto boiling for an hour. Precipitation is then'efi'ected withldilute hydrochloric EtCICl, and the separated product is further treated in the same manner as-the first condensation product obtained'in Example 1, with which it is identical.

In place of the-ethyl ester of B zl benzaup 'thronyl-thioglycollic acid,'other esters of the Bzl-benzanthronyl-thioglycollic acids can be 'ected to the action'of-alkaline condensing agents-in a'similar manner.

' Example, 4

5 parts of Bzl-benzanthronyl thioglycollo11'itrile, of a melting pointfrom 205 to 5 208? (1., which has probably the formula:

onrcN red fluorescence.

' For" conversion into the condensation prodnot with vat dyestuff character, the product 50 may be treated, for example, in the manner described in Example3. In this case the treatment with the aqueous solution of alkali is prolonged until the evolution of ammonia ceases.

employed.

What we c1aim'-is:

1. A process for the" production of con- ,65 densation products otfthe benzanthrone seand which may be prepared for example by condensing sodium, Bzl-benzanthronyl-mercaptid with monochloracetonitrile, and {parts of powdered potassium hydroxid are introduced, while stirring, into 100 parts of pyridine, and stirring is continued until the color of the reaction'mixture ceases to change, 7 which will be the case, for example, after about 72 hours. The color will then be blue with a reddish tinge, .The melt is stirred into ice water containing an excess of hydroohloric acid, and the'pro'd'uct is filtered off, washed with water and boiled several times with a little alcohol. The product left undissolved bythe alcohol can be recrystallized for example, from monochlorbenzene. The compound is insoluble in sodium carbonate solution, sparingly soluble, with red a dish color and yellow fluorescence, in dilute caustic soda solution, and soluble with inte'nse red color with a bluish tinge and yellow fluorescence, inialcoholic caustic soda solution; The solution in concentrated sulfuric acid is blue, with greenish tinge and lies which comprises actingon a compound corresponding to the formula:

wss/

1 2 KCHr-COOH in which the 2-position must be free and the carboxylic group may be substituted by such other groups as are capable of being saponi- 'fi'ed't'o a carboxylic group, with an alkaline condensing agent.

'2. A process for the production of vat dyestufis of the benzanthrone series which comprises acting on a compoundcorresponding to the'formula:

in which the 2-position must be free and the carboxylic group may be substituted by such other groups as are capable of being saponified to a carboxylic group, with an which comprises acting on a compound corresponding to the formula: a

in which It stands for azgroup capable of beingsaponified into a carboxylic group, with an alkaline condensing agent and preciptating the condensation product by dilute acid.

I r 4. A process for the production of condensation products of the benzanthrone series which comprises acting on'a compound corresponding to the formula f s-oHEn, 1.1. V

in stands fora group capableof vbeing saponified into-a carboxylic group, with an alkaline condensing agent, precipitating the condensation product by dilute acid, saponifyingthegcondensation product with v caustic alkali and separating the reaction product with an acid. 5. A process for the production of vat dyestufls of the benzanthrone series which comprises acting on a compound corresponding to f the formula:

in which'R stands for a group capable of being saponified to a carboXylic group, with an alkaline condensing agent, precipitatingthe condensation product by dilute acid, saponitying it andconverting it into a vat dyestu'fi by the action of a mild oxidizing agent.

6. A process for the production of vat dyestufis of the benzanthrone series which comprises acting on a compound corresponding to the formula:

prises acting on a compound corresponding to the formula with an alkaline 'condensingagent in the absence of water, precipitating the condensa- 7 tion product by dilute acid, saponifying it, separating the saponified product by an acid,

and converting it intoavat dyestu'flf by warming its solution in an inert solvent in the presence of a mild oxidizing agent.

8. The process for the production of a vat dyestuii of the benzanthrone series which comprises acting on the ethyl ester of B21- benzanthronyl-thioglycollic acid in pyridine with "caustic alkali, precipitating the condensationproduct by dilute acid, saponifying it by warming it withan aqueous caustic alkali solution, precipitating the ,saponified prod: not by an acid and converting it into a vat dyestulf by Wanning its solution in trichlorbenzene in the presence of air.

9. As new articlesof manufacture condens ation products of the benzanthrone series probably corresponding to the formula;

1 in which the carboxylic group may be substituted by such other groups as are converted into a carboxylic group by saponilication said products beingins'oluble in dilute acids and obtainable by treating a compound corresponding to the formula:

-on,ooon

in which the 2-position must be free and the oarboxylic group may be substituted in the aforesaid manner with'an alkaline condensing agent, said products being soluble in aqueg3 ous alcoholic caustic alkali solution as a rule to a red solution with a yellow fluorescence.

10. As new articles of manufacture condensation products of the benzanthrone series corresponding to the formula:

CH-R

in: which R stands for a CN, CONH or a COR group R standing for an alkyl group, the products being soluble in aqueous'alcoholic alkalis as a rule to a red solution with t a yellow fluorescence, obtainable from a compound corresponding to the formula:

CHI-R in which R is defined as above, by treatment with an alkaline condensing agent.

11. As a new article of manufacture the compound corresponding to the formula: 

